This was an absolute joy.
I've heard contrasting views when it comes to adding coloured lights and fog to the classic ID1 style; to me this episode is absolute proof that when done right it can REALLY work. I felt so deeply engrossed throughout every moment in this, there was an omnipresent foreboding atmosphere that felt undeniably Quakey, everything was perfectly scaled and layouts were kept varied and interesting. Detailing was consistent with no stone left unturned, and there were plenty of pleasing angles in the brushwork.
I liked the nonlinearity; the maps were small enough with distinctive enough areas that getting lost was only ever temporary. I did not find many secrets but the ones I did were great fun, will definitely replay at some point and go for 100% (including the secret level which I missed).
Rarely did I have issue with the gameplay, I liked that it wasn't too overengineered for the most part, but that monsters were generally placed effectively and there was room for a few surprises. It got a bit easy at times once I had the RL but I also got (fairly) punished for using it too brashly! In principle I liked the inclusion of the platforming elements in the runic maps (the tightrope section especially had me clenching a lot), although had a couple of suggestions for improvement I posted in the discussion section.
Overall this is top drawer. Hopefully id get in touch with you to get it included as an official rerelease addon, it would fit right at home on there!